The invention relates to electrically powered or hybrid motor vehicles and more particularly to the coupling of an electric motor shaft with a wheel shaft.
Hybrid vehicles comprising two drive systems, i.e. a heat engine and an electric motor, are known. Conventionally, when switching from one type of propulsion to another type of propulsion, the couplings between the shafts are established between shafts rotating at the same speed. For example, within a vehicle travelling at a certain speed, the coupling between the shaft of an electric motor and that of the wheels will cause jolting if the shaft of the electric motor does not rotate at the same speed as the wheels of the vehicle. The coupling or the decoupling can be implemented when a speed threshold is reached.
It is therefore necessary to control the speed of the electric motor in order to make this equal to that of the shaft of the wheels during a coupling phase (for example when the speed falls again below a threshold).
To this end, it has been proposed in European patent application EP 2 138 371 to implement a method in which an electric motor is controlled around a speed of rotation close to, but not necessarily equal to, that of the shaft of the wheels, and a mechanical synchronization device is then used to obtain an equalization of the speeds. This solution has the disadvantage of requiring a mechanical synchronization device.
In addition, it is necessary to quickly bring the speed of the electric motor close to that of the wheels in order to obtain an almost instantaneous coupling. Further existing solutions make it possible to quickly increase the speed of the electric motor, but once equality has been obtained, the speed of the motor may continue to rise, which causes jolting.